My 7 year old son has a Mirraco Icon with the stock 20x2.125 tires, Alex C303 rims. He's going to try his first triathlon in about a month, and I'm looking for some faster street tires to put on for the triathlon (just a 2 mile bike ride). Would 20x1.5 (40-406) tires fit on his rims? Like these:
http://www.biketiresdirect.com/pkekw...a_kwest/pp.htm

Or do you have any better suggestions?
Thanks!